Hydraulically operated equipment

ABSTRACT

Hydraulic equipment including at least one ancillary assembly in a pressure relief by-pass circuit arranged to impart an added and different motion to the normal motion of the implement and utilizing energy for this purpose which is normally dissipated as waste.

United States Patent Luck [15] 3,677,426 51 July 18,1972

1541 H YDRAULICALLY OPERATED EQUIPMENT [72] Inventor: Dieter G. Luck, 2 Aandblom Avenue,

Kempton Park, Republic of South Africa [22] Filed: Dec. 19, 1969 [21] Appl.No.: 886,667

[52] U.S.Cl. ..2l4/l38R,214/762 [51] Int. Cl. ..E02f 3/00 [58] Field of Search ..2l4/762, 138; 37/D1G. 18;

[56] References Cited UNITED STATES PATENTS 2,619,748 12/1952 McIntosh ..37/D1G. 18

3,084,817 4/1963 Lourenich ..2l4/138R 2,986,294 3/1961 Granryd ..2l4/762 Primary Examiner-Gerald M. Forlenza Assistant Examiner-Jerold M. Forsberg Att0mey-Sh0emaker & Mattare ABSTRACT Hydraulic equipment including at least one ancillary assembly in a pressure relief by-pass circuit arranged to impart an added and different motion to the normal motion of the implement and utilizing energy for this purpose which is normally dissipated as waste.

QIaims 5 prawing Figures Ptented July 18, 1972 3,677,426

2 Sheets-Sheet 1 15a fig. 2a

/ i k Z R 6KHOKD Liick Patented July 18, 1972. 3,677,426

2 Sheets-Sheet 2 a 2 rm zu-rmz DIL'TE!" ER [afar Arr IIYDRAULICALLY OPERATED EQUIPMENT This invention relates to hydraulically operated equipment and more particularly to such equipment which has to meet differing working loads.

Hydraulically operated equipment is today very widely used in earth moving equipment and the like and such equipment is generally fitted with safety means which ensure that working pressures in the various piston and cylinder assemblies do not exceed any predetermined amounts. Normally oil, under overload conditions, is forced through the relief valves, which generally provide the safety features referred to above, and

returned to the reservoir direct. This oil has considerable energy stored therein which is wasted by conversion to unwanted heat.

It is the object of this invention to provide a means whereby hydraulic equipment can be used more effectively under heavy load conditions than has been generally possible heretofore.

According to this invention there is provided hydraulic equipment including safety by-pass fluid circuits comprising at least one ancillary operating assembly in the form of a hydraulic motor connected in said by-pass circuits and adapted to impart an added and different motion to the normal motion of the equipment implement.

The invention also provides for the hydraulic motor to be connected to the implement through a mechanical eccentric rocking mechanism.

Preferred embodiments of this invention are described below with reference to the accompanying diagrammatic drawings in which:

FIGS. 1 and 2 show two layouts of the hydraulic system,

FIG. 2a diagrammatically illustrates a characteristic of certain valves shown in FIGS. 1 and 2,

FIG. 3 shows diagrammatically an eccentric fitted into the implement assembly of earth moving equipment,

FIG. 4 illustrates diagrammatically a different eccentric assembly to give a different movement to the implement, and

FIG. 5 shows in diagrammatic form a plan of a motor arrangement for driving the eccentrics of FIG. 3 or FIG. 4.

In these embodiments the invention is applied to a hydraulic excavator having a shovel as the implement. It is to be understood that the invention is not confined to this type of equipment but may be adapted for all hydraulically controlled equipment subjected in use to varying load conditions.

In the embodiments shown in FIGS. 3 and 4 the excavator has the standard piston and cylinder assemblies 1 for operating the shovel.

Each assembly includes an eccentric arrangement 2 but differently located in the linkages. These eccentrics are adapted to be driven by a hydraulic motor which is brought into operation only under heavy load conditions as described in detail below.

It will be understood that the rotation of the eccentric as shown in FIG. 3 will give a reciprocatory motion to the implement working tip 3. The path of this motion will be along an arc of a circle with center at the pivot point 4 for the shovel 5.

The arrangement of the eccentric 2 as shown in FIG. 4 gives a motion to the working tip which is along an elliptical path. The dimensions of the path are of course dependent on the design of the eccentric and linkages.

FIG. 5 shows the mounting of the hydraulic motor 13 in the yoke of the dipper arm of a shovel and directly connected to drive the eccentrics 2. It has been found that a hydraulic motor made by Rollstor A.G. Machinenfabriek 4800 Zofingen, Kornweg 2, Switzerland, and sold under the name Rollstor M 50 d" is most suitable for this purpose. With this assembly the drive shaft 13' of the motor 13 projects on either side of motor 13 thereof for direct connection to the eccentrics 2 as indicated. Thus it will be appreciated that no great changes to existing machinery need be made to include this invention in the construction thereof.

For the invention to achieve the objects set out above a simple hydraulic control arrangement is shown in FIG. I.

In this arrangement the working piston and cylinder assembly l 6 is fed in a double acting manner from a reservoir indicated by numeral 7 via lines 8 and 9. The one line 8 feeds the left hand of the assembly through a check valve 9 and the other line I0 for the return stroke of the piston in the assembly 6 has a control connection II to the check valve 9 so that the latter can be maintained open when the piston is on the return stroke.

Thus under working conditions which create conditions of pressure in piston and cylinder assembly 1 below that which would open the normal form of relief valve, the flow of fluid through lines 8 and I0 is conventional.

However, when the pressure exceeds that predetermined value, valve 12 opens and the hydraulic motor 13 is operated to rotate the eccentric 2 described above. The flow through the hydraulic motor 13 passes through a protective non-return valve 14 to reservoir 7.

It will be appreciated that the movement of the eccentric applies a greater than normal pressure to the working tip 3 of the implement and the reaction to this pressure is taken up in the assembly I. This causes a build up in pressure in assembly I and if a higher predetermined pressure is reached a second relief value 15 opens allowing discharge of fluid through line 16 back into the reservoir circuit and the pressure of this fluid will drop to that passing through motor 13 and the flow will act to speed up the motor due to the increase in volume through the motor which is, at that stage, supplied both from the reservoir and from line 16.

With this arrangement it will be seen that movement of the eccentric under overload conditions forces the working tip against the operating face with pressure in excess of those for which the usual pump mechanisms are designed. Also, the working tip will not generally, where the eccentric arrangement is as shown in FIG. 3, return along the path because the return motion will be counteracted by movement of the piston in the cylinder of assembly I.

To obtain a chopping or hammering action under overload conditions, the eccentric arrangement of FIGS. 3 or 4 and hydraulic circuit of FIG. 2 is preferred.

Under normal conditions and overload conditions which do not cause operation of the second relief valve 15, the hydraulic arrangement is identical to that described above and the same numerals are used to indicate similar components in the two circuits illustrated in FIGS. 3 and 4.

To obtain the desired chopping effect the circuit of FIG. 2 includes parallel circuits including in one path 17 a throttle l8 and in the other path 19 a three-position, fast opening/slow closing valve 20, this slow closing of valve 20 causing oil which has flowed to operate the hydraulic piston of valve 20, to be expelled by the spring 20' of valve 20 along line 17 through throttle 18 to reservoir 7.

With this arrangement it will be appreciated that when the pressure in piston and cylinder assembly I exceeds the predetermined value for a short period only valve 15 opens allowing only a small fluid flow, all of which flow is passed through throttle 18 without generation of back pressure. Here again the system operates as described above.

However, when the excess pressure and consequent volume of delivery through the valve 15 is maintained to prevent complete flow through the throttle I8 and causing a build up of back pressure, the valve 20 opens allowing flow through passage 19a and non-return valve 19b feeding line 8 and closing line to the assembly 1, and limiting the pressure build up by the throttle 18. This increased flow accentuates the operation of hydraulic motor 13 also as described above.

The valves used at 12 and 15 are preferably of the known type illustrated at in FIG. 2a and have the characteristic of opening at a certain pressure independent of the pressure in the outlet line.

However, when the excess pressure in the piston and cylinder assembly 1 is alleviated the valve 20 cannot open the normal line 8 instantaneously and this enables the working tip to move off the operating face since movement of the eccentrio is not compensated for by a pressure rise in the piston and cylinder assembly 1. This is because the pressure will drop when the tool moves from the working face and fluid cannot be delivered thereto through valve 20. Thus, with a proper design of eccentric and linkage arrangement with regard to the delay period of operation of valve 20, a hammering action on the operating face can be obtained when the resistance to normal operation of the shovel causes excessive pressures in the hydraulic system to occur.

From this it will be appreciated that under heavy load conditions a different movement is applied to the shovel 5 than when easy conditions are encountered. This different motion enables effective excavation to be achieved where normal machines of the same capacity would not be able to operate.

Under some conditions it may be desirable to include buffers to absorb the shock loading on the excavator caused by the jigging movements imparted to the shovel. Also component parts of the machine will be designed to give optimum resultant force and movement of the shovel.

it will be understood that an overriding relief valve will be included in either of the systems above described to control the maximum pressures operating in the combined assemblies.

The invention provides a means of effectively utilizing all the energy generated in hydraulically operated equipment even under overload conditions.

Thus, generally the invention includes a hydraulic excavator including a dipper arm yoke means, a shovel implement, and a first pivot means mounting said implement on the end of said dipper arm yoke means. A hydraulic operating means is provided for actuating said shovel implement which includes a piston and cylinder assembly pivotally mounted on said dipper arm yoke means, lever means, second pivot means pivotally connecting said lever means to said dipper arm yoke means, third pivot means pivotally connecting said lever means to one of said piston and cylinder of said assembly and linkage means pivotally connected between said lever means and said shovel implement. There is a hydraulic circuit for said operating means that includes safety by-pass components comprising an ancillary operating assembly for said implement fed by said components and including a mechanical eccentric rocking mechanism embodied with one of said first two mentioned pivot means and a hydraulic motor mounted in said dipper arm yoke means and directly connected to said eccentric rocking mechanism to impart an added and different motion to the implement. In FIG. 3. the eccentric rocking mechanism is embodied with the second pivot means between the lever and the yoke means, whereas in FIG. 4 the rocking mechanism is embodied with the first pivot means between the implement and the yoke means.

What I claim as new and desire to secure by Letters Patent is:

l. Hydraulically operated earth moving equipment comprising an operating tool; a linkage system connecting the tool to the equipment; a hydraulic piston and cylinder assembly and supply circuit for controlling the linkage system; a rotatable eccentric mechanism in the linkage system; a hydraulic motor connected to the eccentric mechanism; a safety by-pass hydraulic circuit in the piston and cylinder circuit including a pressure controlled valve; parallel outlet paths from the valve; a throttle in one path and a fast opening, slow closing valve in the other path; the latter valve adapted to close the normal circuit to the piston and cylinder assembly when open and having its outlet connected to the hydraulic motor.

2. Hydraulically operated earth moving equipment as claimed in claim 1 in which the hydraulic motor is connected through a pressure controlled valve in parallel with the circuit to the piston and cylinder assembly.

3. Hydraulically operated earth moving equipment as claimed in claim 2 in which the pressure controlled valve operates independently of the pressure applied to the outlet thereof.

a a a 4 4' 

1. Hydraulically operated earth moving equipment comprising an operating tool; a linkage system connecting the tool to the equipment; a hydraulic piston and cylinder assembly and supply cIrcuit for controlling the linkage system; a rotatable eccentric mechanism in the linkage system; a hydraulic motor connected to the eccentric mechanism; a safety by-pass hydraulic circuit in the piston and cylinder circuit including a pressure controlled valve; parallel outlet paths from the valve; a throttle in one path and a fast opening, slow closing valve in the other path; the latter valve adapted to close the normal circuit to the piston and cylinder assembly when open and having its outlet connected to the hydraulic motor.
 2. Hydraulically operated earth moving equipment as claimed in claim 1 in which the hydraulic motor is connected through a pressure controlled valve in parallel with the circuit to the piston and cylinder assembly.
 3. Hydraulically operated earth moving equipment as claimed in claim 2 in which the pressure controlled valve operates independently of the pressure applied to the outlet thereof. 